Abstract: Molecular stacking in zinc perfluorophthalocyanine(F₁₆PcZn) thin films deposited on quartz wafer at different temperatures was systematically investigated. UV-Vis absorption spectra, X-ray diffraction(XRD) patterns and atomic force microscopic(AFM) images reveal a three-step growing mechanism ranging from room temperature to 300 ℃. Firstly, a “card-packing” ground layer forms by the strong interactions between F atoms on F₁₆PcZn molecules and quartz substrate. Secondly, an “amorphous accumulation” transition layer grows on the top of the ground layer. Finally, a highly ordered “brick-stacking” crystalline layer is built up. The corresponding absorption features of these three stacking modes was shown at around 640, 670 and 810 nm respectively. The temperature-dependent variation of the feature at 810 nm indicates that the “brick-stacking” is a favorable mode at the elevated temperature. AFM images show that the F₁₆PcZn crystalline domain sizes increase with raising temperature. XRD data demonstrate that, at atmosphere temperature, the F₁₆PcZn molecules arrange in a monoclinic lattice with a constant of a=1.494 nm, while from 250 ℃ to 300 ℃, the molecular stacking evolves to a more compact mode with a little shorter constant of a=1.428 nm.

Key words: Molecular stacking, Surface morphology, Thin film